The present invention relates to a fragrant composition having a mosquito-repelling effect, which comprises containing a mixture made of specific compounds obtainable from plant essential oils as an effective ingredient.
That is, it relates to a fragrant composition having a mosquito-repelling effect, which comprises containing a mixture made of isomenthone, linalool, geraniol, citral and citronellol as an effective ingredient.
Furthermore, it relates to a fragrant composition having a mosquito-repelling effect, wherein the mixture further contains a fatty acid having 8 to 10 carbon atoms.
Heretofore, many mammals including human have continued to suffer from action of mosquitoes. For example, sucking of blood by a mosquito results in an itching sensation and an outbreak of a rush, dermatitis, or the like and hence causes a very unpleasant feeling. As one means for solving the problems of the suffering or unpleasant feeling, there is known a method of applying a mosquito-repelling agent to the surface of human skin.
N,N-Diethyl-m-toluamide (hereinafter, referred to as DEET) having a mosquito-repelling effect is currently employed commonly in various products as a mosquito-repelling agent. However, DEET has a remarkably high persistency of the mosquito-repelling effect, but it has problems of outbreak of dermatitis and cranial nerve injury when the use is continued for a long period of time, a possibility of carcinogenesis owing to its high skin-permeability, and a poor biodegradability and a high accumulative property.
Accordingly, a safe mosquito-repelling agent exerting no adverse effect on human and environment has been desired.
Thus, for the purpose of developing a mosquito-repelling agent which is gentle to the environment and safe to human body, and has a mosquito-repelling effect, the present inventors have focused on Pelargonium citrosum which is known to have a mosquito-repelling effect and isolated an essential oil from the plant.
However, it has been found that the essential oil of Pelargonium citrosum has a satisfactory mosquito-repelling effect but the sustained effect is not sufficient.
Therefore, it is an object of the invention to provide a mosquito-repelling agent which has an excellent mosquito-repelling effect almost equal to the effect of DEET, is gentle to the environment and safe to human body, and also has an excellent persistency. Furthermore, it is also an object to provide a mosquito-repelling fragrant composition having a pleasant smell for consumers.
As a result of intensive studies for solving the above problems, based on the information on fragrant ingredients obtained by the fragrance analysis and dynamic head space analysis of the distillate from steam distillation of Pelargonium citrosum, the inventors have found that a fragrant composition containing a mixture made of specific compounds, more specifically, a fragrant composition containing a mixture of the compounds having a specific weight ratio has a strong mosquito-repelling effect equal to or higher than the effect of DEET and also has a satisfactory persistency of the mosquito-repelling effect which is different from the distillate from steam distillation of Pelargonium citrosum. 
In addition, the fragrant composition of the invention exhibits no irritation toward skin and has a high safety. Furthermore, the inventors have found the advantages that the fragrance tone can be widely changed by using other fragrant material(s) in combination and that the composition has less sticky feeling toward skin as compared with DEET. Based on the findings, they have accomplished the invention.
Namely, the invention relates to:
1) a fragrant composition having a mosquito-repelling effect, which comprises containing a mixture made of isomenthone, linalool, geraniol, citral and citronellol, as an effective ingredient;
2) the fragrant composition, wherein the weight ratio of the above compounds in the mixture is, on the basis of isomenthone, that linalool, geraniol, citral and citronellol are 0.5 to 2.0, 2.0 to 5.0, 0.5 to 2.0, and 2.0 to 4.0, respectively;
3) the fragrant composition, wherein the mixture further comprises a fatty acid having 8 to 10 carbon atoms;
4) the fragrant composition, wherein the weight ratio of the above fatty acid is 0.05 to 2.0 on the basis of isomenthone; and
5) the fragrant composition, wherein the fatty acid is decanoic acid and/or rhodinic acid.